You dunk it in water and it "grows 600% in 72 hours" - my sons first thought it was 600 times which would have been wild! I have a webcam watching my grass grow and others for my crazy halloween decorations and christmas lights ... so I figured it would be fun to set the penguin up front of a webcam to watch it grow. Here's some time-lapse video so you can relive the excitement: dunk in water - 4 hours - 12 hours - 24 hours - 48 hours - 72 hours
I measured the penguin beforehand at 3 3/8" tall before I dunked him in the water at Noon on Nov 17th, 2008. One problem was he floated ... so he kept falling over ... even after lowering the water level. Next time, I'll use a glass rather than a bowl.